Alkanolamines have been known for decades and generally comprise an alcohol function and an amino function as a part of the same organic molecule. Some of the simplest alkanolamines include those known by those in the art familiar with saponification, such as the ethanolamines: mono-, di-, and tri-ethanol amines. The number of higher ethanolamines which are possible is great, as the chain length of the hydrocarbon portion of a given alkanolamine molecule can be varied from about 2 carbon atoms to upwards of hundreds of carbon atoms in the case where the alkanolamine is derived from a polymeric substrate. While it is to the higher alkanolamines to which the present invention is primarily directed; the instant process is applicable to production of the lower alkanolamines as well. However, the benefits conferred through use of the invention are most pronounced in the case of the production of alkanolamines having molecular weights in excess of about 500.
Alkanolamines, or hydroxyalkyl amines as they are sometimes referred to, are useful as additives for motor fuels, including, but not limited to those motor fuels defined by ASTM specification D-439-73, as such amines tend to reduce or eliminate unwanted deposits in the intake manifold, runners, intake valve, and valve bowl area of a conventional automobile engine. Examples of patents describing the use of such materials for this purpose include the international patent application filed under the PCT identifiable as international publication number WO 92/14806 of Ferro Corporation, Cleveland, Ohio, USA, published Sep. 3, 1992, European Patent Specification EP 0 516 838 B1 (International Publication number WO 92/12221), (Chevron Inc.), published Jul. 23, 1992, and European Patent Specification EP 0 476 485 B1, (BASF) published Mar. 25, 1992, the entire contents of all three of which references are herein incorporated by reference thereto. The use of these materials as additives for motor fuels is particularly attractive owing to the fact that they are halogen-free, which means that organic halogen compounds are not formed as a result of their combustion.
One synthetic route by which alkanolamines of high molecular weight may be prepared is the multi-step process wherein a polyolefin is first converted to an epoxide by means known to those skilled in the art. Such means may be effected on any polyolefin, but the polyolefins polyethylene, polypropylene, and polybutylene have been traditionally preferred. Generally, an olefin homo- or co-polymer having a molecular weight in the range of 170 to 5000, preferably 300 to 4000, more preferably 400 to 3500, and most preferably 500 to 3000, is charged to a reactor along with an effective amount of hydrogen peroxide, and especially preferably along with a catalytic amount of a carboxylic acid, which catalyzes the epoxidation of the olefin by presumably forming a peroxy acid as an intermediate. The reaction is carried out at a temperature in the range of about 60 to 85 degrees centigrade, and other conditions for such a reaction is described in Organic Peroxides, Vol. 1, Wiley-Interscience, New York, 1970, Daniel Swern at pages 340-369, inter alia, the entire contents of which are herein incorporated by reference thereto, as well as the patent publications already mentioned. Additionally, it has been found by some workers to be convenient to employ a hydrocarbon solvent in which to carry out the epoxidation. Typically, as is evident from the prior art cited herein, several hours are required to effect a significant degree of reaction between an epoxidized polyolefin and an amino compound, with reaction times on the order of 10 to 16 hours being typical. Through use of the instant invention, the reaction time may be reduced to only 2 to 3 hours. Reaction conditions are described in the prior art herein incorporated by reference.